Process of converting hydrocarbons



Jan. 14, 1941. M. P. YOUKER Paocss `QF cNvERTING HYDaocABoNs 2 Sheets-Sheet 1 Filed Nov. 25, 1935 Ill' Jan. 14', 1941. M. P. YOUKER PROCESS OF CONVERTING HYDROCARBONS Filed Nov. 25, 19:55

2 Sheets-Sheet 2 Summa/1p Patented Jan. 14, 1941 PROCESS OF CONVERTING HYDROCARBONS Malcolm P. Youker, Bartlesville, Okla., assignor to Phillips Petroleum Company, Bartlesville,

Okla., a corporation of Delaware Application November 25, 1935, Serial No. 51,506

2 Claims.

The present invention relates to improvements in processes for simultaneously converting normally gaseous hydrocarbons and normally liquid hydrocarbons, and the present application is a continuation-in-part of my applications Serial Nos. 481,318, led September 11, 1930 (Patent No. 2,027,460), and 527,267, filed April \2, 1931, which applications are in turn based upon the disclosure in the application which matured into my U. S. Patent N0. 1,800,586, dated April 14,

The objects of the present invention appear in the following description which is to be considered in connection with the accompanying drawings.

In the drawings,

Fig. 1 is a diagrammatic side elevation of one form of apparatus by which my new improvements may be carried out. v

Fig. 2 is a similar View of a modification.

Referring to Fig. 1 of the drawings, the numeral I designates a furnace through which certain pipe lines are passed. The numerals 2, 3, 4, 5, 6 and 1 designate cylindrical closed vessels which are used for separating vapors and gases from liquids. Pipe lines in which condensation takes place are passed through condensers 8, 9, I and II. Bubble trays I2 are disposed in fractionating columns I3 and I4 and an absorbing tower I5.

Hydrocarbon gases in either liquid or vapor phase will be delivered through a pipe line IIB in which is mounted a Valve I1, a pump I9 and a valve I8 and through furnace I into separator 2. Liquid which will collect in separator 2 will flow thence through a pipe 23 in which is mounted a valve 2I into the fractionating column I3. Liquid which will collect at the bottom of iractionating column I3 will flow thence through a pipe 22 in which is mounted a valve 23 into the fractionating column I4. Liquid which will collect at the bottom of fractionating column I4 may ow thence through a pipe line 24 in which is mounted a valve 25 into separator 1. Liquid or tar which may accumulate in separator 1, will be discharged therefrom by a pump 26 through a pipe lin-e 21 and a cooler which is not shown. Vapors and permanent gases will pass from the top of separator 2 by way of a pipe line 28 through condenser 8 into separator 3. Vapors and gases will pass from the top of fractionating column I3 by way of a pipe 29 through condenser 9 into separator 4. Vapor and gases will pass from the top of fractionating column I4 by way ot' a pipe 30 through condenser I!! into separator 5. Vapors will pass from the top of separator 1 by way of pipe line 3I through condenser II into separator 6. Gases such as eX- cess hydrogen, hydrogen sulphide, nitrogen, and helium will be vented from the system through a pipe line 32 in which is mounted a back pressure valve 33 and which leads from the top of separator 3. Gases may be vented from the top of separator 4 through a pipe 34 in which is mounted a back pressure valve 35. Gases .may be vented from the top of separator through a pipe 36 in which is mounted a back pressure valve 31. A pipe' 38 in which is mounted a vacuum pump 39 leads from the top of separator B. The vacuum pump 39 may be operated to maintain a vacuum ln separators 6 and 1 and their inter-connecting pipe line 3l. Liquid which will accumulate in the bottom of Vseparator 3 will be pumped by a pump 40 through a pipe line 4I and valve 84 into pipe-l I6 at a point between the pump I9 and the furnace I. Liquid which will accumulate in the separator 4 will be delivered by a pump 42 throu'ghra pipe 43 and through pipe 4I into the pipe I6 at a point between pump I9 and the furnace I. Liquid which will collect in the bottom of separator 5 will be delivered thence through a pipe 44 in which is mounted a valve 45. Liquid which will accumulate in the bottom of separator 6 may be delivered thence by a pump 46 through pipe 41 and valve 48. A compresser 49 may be operated to deliver gas from the top of separator 3 through pipe 32 and a pipe 50 and a Valve 5| into pipe I6 at a point betweenpump I9 and furnace I. By means of manipulating a valve 52 which is mounted in a pipe 53, gas and vapor may be delivered from separator 2 byv a compresser 49 into pipe I6 at a point between pump I9 and furnace I. erated to deliver gas through pipe 34 and pipe 55 and a valve 56 and pipe 50 from the separator 4 into the pipe I6 at a point between pump I9 and furnace I. A reflux liquid will be delivered from the bottom of separator 4 by means of a pump 51 through a pipe 58 into the top of fractionating column I3. Liquid will be `delivered from the bottom of separator 5 by` means of a pump 59 through a pipe 50 into the top of fractionating column I4. Liquid will be forced by a pump 6I through a pipe 62 which leads from the bottom of fractionating column I3 through the furnace I and back into-.the bottom Aof the fractionating column I3.- Liquidfwill. be forced from the bottom of fractionating column I4by a pump 53 through a pipe 64 which leads through A compresser 54 may be yO11-, v

the furnace I and back into the bottom of fractionating column I4. A pipe in which is mounted a valve 66 and which is in communication with an extraneous supply of hydrocarbon liquid such as fuel oil or gas oil, leads to a pump 61. A pipe 68in which is mounted a valve 66, leads from the discharge of pump 6'I into the pipe I6 at a point between pump I9 and furnace I. A pipe 'I0 in which is mounted a Valve II leads from the discharge of pump 6'! into the top of an absorber I5. A pipe I2 in which is mounted a valve 'I3 leads from the bottom of absorber I5 into pipe line I6 at a point on the suction side of pump I9. Heavy oil such as fuel oil or gas oil may be deliveredby the pump 6l through the pipes 65 and 68 into the pipe line I6 at a point between the pump I9 and furnace I, or such heavy oil may be delivered by the pump 61 through the pipes 65 and I0 into the absorber I5 and thence through pipe I2 into the pipe I6 and thence to pump I9. Gas may be delivered through pipe I6, a pipe 14, and a valve I5 into the bottom of absorber I5 and thence through absorber I5 and a pipe 'I6 in which is mounted a vback pressure valve 1l. Heavy oil such as fuel oil or gas oil or crude oil may be delivered through a pipe 'I8 in which is mounted a .Valve 'I9 by a pump 80 into the pipe I6 at a point between furnace I and separator 2. A pipe 8| in which are mounted valves 82, 83 and 9|, connects into pipe 'I8 on the suction side of pump 80 and connects into the pipe 65 on the suction side of pump 6T. A pipe 85 in which is mounted a pump 86 and a valve 8l leads from the bottom of fractionating column I4 into pipe 8I. A pipe 88 in which is .mounted a pump 89 and a va1ve90 leads from the bottom of separator 6, into pipe 8l. By means of the pump 89 'and the valves and pipes shown, liquid may be delivered from the bottom of separator 6 to the suction side of either of the pumps 6l or SIB.V By means of the pump 86 and .the valves and the pipes described, liquid may be delivered from the bottom of fractionating column I4 to the suction sideof either pump 6l or pump 86. A pipe 92 in which is mounted a valve 93 connects into pipe .85 at a point between pump 86 and valve 81 and liquid may be withdrawn from the bottom of fractionating column I4 through this pipe 92 and delivered to storage through a cooler which is not shown.

Hydrocarbon liquids may be made from hydrocarbon gases by two methods which are closely l related. These methods of gas conversion may be used separately or may be combined in the same process. The apparatus shown may be used to carry out either one of these methods or the vcombination of the two methods. For purposes of. clarity, I will describe these Amethods separately. 'Some of the hydrogen may be removed fromhydrocarbon gases and the remaining hydrogen content vof such gases be simultaneously recombined with 4the carbon content of such gas `to form a liquid hydrocarbon, or carbon may be added to hydrocarbon 'gases and combined with excess hydrogen .contained 'in such gases to form a hydrocarbon liquid. The former case would be de-hydrogenation of hydrocarbon gases and the latter case wouldbe carbonization of hydrocarbon gases.v4 Y 1 l The apparatus shown will be used to de-hydrogenate gas in the following manner: Hydrocarbon gas in either| liquid or gaseous state will be delivered by pump I9 through the pipe I 6 and will be heated therein to a temperature preferably be.

tween '700 degrees F. and 1000 degrees F. I iind that good results may be obtained at 875 degrees F. and that when this temperature is obtained under pressures between 2,000 and 3,000 pounds per square inch, a good conversion from gases to liquids is obtained. After the conversion of part of the gases to liquid has taken place in the pipe I6, cold hydrocarbon liquid will be delivered into said pipe i6 through the pipe l0 by means of the pump 86 in order to ccol the mixture of gases and liquid down to such a temperature, say 400 degrees to 600 degrees F., that only gases which are more volatile than gasoline will remain in the Vapor or gaseous phase, the cooled converted gases and liquid, together with the hydrocarbon liquid which was extraneously supplied, will then flow into separator 2. Gases and vapors which are more volatile than gasoline will then ow through pipe Z8 and condenser 8 into separator 3. The gases and vapors passing through condenser S will be cooled and a mixture of liquid and gas will be delivered into separator 3. The material which remains in a gaseous state after passing condenser 8 will be vented from separator 3 and the system through pipe 32 and back pressure valve 33. Some of this gas delivered into separator 3 may be charged to the process through pipe I6 by means of the pipe 50 and the pump 49, Liquid which will collect in separator 3 will be withdrawn therefrom and recirculatedthrough the pipe i6 and thereby through the process by means of pump 40 and pipe 4I. in separator 2 will contain material which is more volatile than gasoline. This liquid will be delivered from separator 2 through pipe 20 into fractionating column I3. The fractionating column I3 will be reboiled by means of circulating liquid through the pipe 62 and through the furnace. Vapors will flow from fractionating column I3 through pipe 29 and ce cooled and condensed in condenser 9 and will ow thence into separator .4. Liquid will be reluxed from the bottom of separator 4 by pump 5'! through pipe 50 into the top of fractionating column I3 and a temperature at the top of fractionating column I3 will be maintained such that only liquids which `are more volatile than gasoline will leave the fractionating column I3 in the Vapor phase through the pipe 29. Liquids which collect in separator 4 will be recharged to the apparatus through the pipe I6 bymeans of the pump 4.?. and the pipes 43 and 4I. Permanent gases which may collect in separator 4 will be vented from the system through pipe 34 and back pressure valve 35. Gases which collect in separator l may be recharged to the apparatus through pipe I6 by .means of pump 54 and pipes 55 and 50. Liquid which contains gasoline and heavier hydrocarbon material will be discharged from the bottom of fractionating column vI3 into the fractionating column I4. I4 will be reboiled by means of circulating liquid through the pump 63 and the pipe 64, and through the furnace. Vapore will be discharged from the fractionating column Il through the pipe 30 and will be cooled and condensed by the condenser I0 and will flow in liquid forni into the separator 5. Liquid will be refiuxed from the separator 5 by the pumpr59 through the pipe 60 into the top of fractionating column I4, and the temperature at the top of fractionating column I4 will be so maintained that only gasoline vapor will discharge through the pipe 36. Gasoline will be withdrawn from the system through the pipe 44 and the valve 45. Any gases which may accu- Liquid trapped Ano The bottom of fractionating column mulate in separator 5 will be vented therefrom through the pipe 35 and valve 31. Liquids which are heavier than gasoline, that is, fuel oil and gas oil, may be withdrawn from the bottom of fractionating column I4 through the pipe 85, pump 86, valve 93 and pipe 92 to storage, or such liquids may be recirculated through the pipe I6 by means of pumps 86 and 61 and pipe line 35, 8 I, 65 and 38,

`or such liquids may be recirculated through pumps 86 and 80 through pipes 85, SI and 1B, or such liquids may be discharged from the bottom of fractionating column I4 into the vacuum distillation unit consisting of separator 1, condenser II, separator 6, and accessory pumps, pipe lines, and vacuum pump 39. This vacuum distillation unit, is conventional and is for the purpose v'of separating gas oil or lubricating oil from fuel oil. Vapors which will be evolved in separator 1 under the low pressure conditions existing therein will pass therefrom through pipe 3l and will be condensed in condenser II and flow into separator 6, while tars which will collect in the bottom of separator 1 will be withdrawn therefrom by pump 2S through pipe line 21. Gas oil which will collect in separator 6 may be recirculated through pipe I6 by way of pipes 88, 8l and 58 or by way of pipes 88, 8| and 18. Through manipulation of valves I8 and 2| and 33, a pressure of between 2,000 and and 3,000 pounds per square inch will preferably be maintained in separator 2 and separator 3 and in pipe lines accessory to the separators. My manipulating valves 23 and 35 a pressure preferably from 400 pounds to 700 pounds per square inch, but sufficiently high to condense in condenser 9 all vapors which pass through pipe 29 will be maintained in the fractionating column I3 and the separator 4 and accessory pipe lines. By manipulation of the valve 31 preferably atmospheric pressure will be maintained in the fractionating column I4, separator 5, and connecting pipe lines. By this method of operation, natural gas or constituents of natural gas may be charged to this apparatus through the pipe I3, and this material will be converted into synthetic crude oil and gases. The apparatus is so arranged that after this conversion has taken place the converted material may be separated into the follow'- ing fractions: Permanent gases which are vented from the system, gases which are more volatile than gasoline and which are recirculated through the process, gasoline which is recovered separately as a product of the process, and hydrocarbon liquids which are heavier than gasoline and which are reciroulated through the process. Gas delivered to the apparatus would ordinarily contain certain permanent gases which if not vented from the system would in a short time ll the system up :and discontinue the operation of the process, alsohydrogen will be continuously evolved within the system, and if this gas is not vented from the system it will become lled with hydrogen and cease to operate. The material produced within the apparatus which is more volatile than gasoline and which is re-cycled through the apparatus is maintained under high pressure at all times and preferably in liquid form in order that recirculation may be accomplished economically. When gas only is supplied from an extraneous source to the apparatus, a considerable quantity of hydrogen will necessarily be vented from the system.

Instead of supplying gas only to this process, fuel oil or gas oil may be supplied from an extraneous source to supply carbon with which to combine the excess hydrogen contained in the gas in which case hydrogen will preferably not be vented from the system and only such permanent gases as are inadvertently introduced into the system with the gas and heavy oil will be separated-from other material in the system and vented therefrom. Liquids which contain a higher percentage of carbon than is contained in gasoline will be introduced into the system either through pipe 65 or pipe 18. In the event that crude oil should be introduced into this system, it should be introduced through the pipe 18 and gasoline contained in this crude oil would' be distilled and separated from the fuel oil and gas oil contained in the crude oil in the fractionating system and the gas oil and fuel oil contained in this crude oil would enter the pipe I6 as a recirculated liquid coming from either fractionating column I4 or separato-r 6. This is an indirect way of introducing fuel oil or gas oil into the system when crude oil only isl available for the purpose.

It will be found desirable in some cases to cool any liquid which is heavier than gasoline and lwhich is introduced into the pipe I5 and to initially use this heavy oil `for an absorbent to absorb constituents of natural gas and subsequently introduce the mixture of heavier than gasoline liquids and lighter than gasoline liquids thus produced into the pipe I6. The absorber I5 with interconnecting lines shown may be used for this purpose. v

As stated in my original application for Letters Patent covering this gas conversion process, I dc not propose to limit the process to natural gas but may use the process to convert other hydrocarbon gases to liquids and it should be understood that the improvements which are divulged and claimed herein may be used in a manner similar to that described to process hydrocarbon gases other than natural gas. I

will probably process hydrocarbon gases which are produced by the cracking Yof heavy oils such as gas oil and fuel oil. In some cases, I will in the manner described herein, add carbon which is contained in heavy oils such as fuel oil or gas oil, to hydrocarbon gases which result from cracking natural gas under comparatively low pressure and at high temperature instead of adding such heavy oils to the virgin natural gas.

y In the embodiment of the invention illustrated in Fig. 2, a mixture of liquefied hydrocarbon gas and hydrocarbon liquid, the source of which will be designated later, will be caused tonow through a pipe Ia which leads through a furnace 2a, into the bottom of a high pressure fractionating column 3a and' in whichis mounted a valve 4a. This mixture will be heated while passing through pipe la and the furnace 2a to a temperature between 750 F. and 950 F. and will be delivered into the bottom of the fractionating column 3d in a partially vaporized state. kVapors thus delivered into the bottom of the fractionating column 3a will flow thence upward through thebubble plates 5a in fractionating column 3a -and thence through a pipe 6a, which leads through a condenser 1a into a gas liquid separator 8a. Part of the vapors which pass through the pipey 5a and condenser 1d will be condensed vtherein and a mixture of gas and liquid will flow from the pipe 8a into the separator 8a. A sufficient quantity of the liquid which willaccumulate in `separator 8a will be delivered by a pump 9a through a pipe Ia in which is mounted a valve IIa, intofthe top of fractionating column Sato condense in fractionating column 3a all of the gasoline and heavier vapors delivered into fractionating column 3a. That part of the liquid which` accumulates in separator 8a in excess of the liquid withdrawn therefrom through pipe I0aY will flow therefrom through a pipe- I2a, into the bottom of an absorbing column lia. Gas will flow from the top of separator 8a, through a pipe |40, into the bottom of absorber 13a and thence upward through bubble plates I5a in absorber l3a and thence from the top of absorber |3a through a pipe Ilia in which; is mounted a back pressure' valve Ila; Liquid will be released from ythe bottom of fractionating column 3a through a pipe I3a in which is mounted a Valve I9a into a fractionating column 20a. By means of the valve I-Sa and the Valve Ila, pressure will be maintained in the fractionatingcolumn 3a in excessl of the pressure which will be maintained in the fractionating column 20a, and as a result, liquid which will flow into fractionating column 20a through the pipe 18a, will partially vaporize upon entry into fractionating column 20av and vapors thus produced will flow upward through bubble plates Zia, in fractionatingY column 20a and thence through a pipe 22u which leads through a condenser 23a into an accumulator tank 2da. A su-icient quantity of liquid will' be delivered from accumulator 'Mal by a pump 25a. through pipe 26a, in which is. mounted a Valve 2101.V into the topofY fractionating column 20a to condense in fractionating column 20a all of theA vapors introduced therein except gasoline vapors. Thus gasoline vapors only will flow through pipe 22a and condenser 23a, and gasoline only will flow into accumulator 24a. A vent line' 28a, in which is mounted a valve 29d is provided for the release from accumulator tank 24a o1 any gas which may inadvertently accumulate therein. Gasoline will be withdrawnv from. the bottom of accumulator tank 24a through a pipe 3&0, in which is mounted a valve 31a. Some of the liquid which will flow downward in the fractionating column 20a over bubble plates 2 la may be withdrawn through a pipe 32a from. one of bubble plates zia which is. located above the point of entry of pipe [tot intoY fractionating column 20a and may be forced by a pump 33a, through a pipe 34a in which is mounted a valve 35a and which leads throughv the furnace 2a into the bottomlof' fractionating column 20a. Liquid which may be delivered throughpipe 34amay be heated in the furnace 2a andithus the fractionating column Za, may be heated. Liquid may be withdrawn from fractionating column 20a throughy pipe 32a` and. may be delivered by pump 33a through a pipe 36a in which is mounted a valve 31a,v into. and through the pipe la. Residue may be withdrawn from the bottom of fractionating column 20a .through a pipe 55a in which is mounted a valve 56a by a pump 51a and may be forced by pump 51a through a pipe 58a into and through pipe la. Distillate may be drawn from one of the bubble plates 2 la through a pipe 38a, in which is mounted a valvee 39a. Fuel oil will be withdrawn from the bottom of fractionating column 20a, through a pipe 40a in which is mounted a valve 41a. Hydrocarbon liquid such as crude oil or fuel oil or the like will be delivered through a pipe 42a, in which is mounted a valve 43a into the top of absorber l3a and will flow thence downward over bubble plates Ia, contacting and absorbing a portion of the gas which will iiow upward through absorber I3a. A mixture of oil and liqueed' gas which will collect in the bottom of absorber I3a will be delivered by means of a pump 45a through a pipe 44a in which is mounted a valve 45u into and through the pipe la. In case a supply of cracked gas is available, such gasfmaybe delivered through a pipe 47a in which is mounted a valve 48a into and through pipe la. Delivery of gas from an extraneous source to the process through the pipe 47a is optional as the process may be carried out either with or without thus supplying gas to the process. A portion of the liquid which flows downward over bubble plates 5a in fractionating column 3a may be withdrawn from an intermediate one of bubble trays 5a and discharged therefrom through the pipe 49a. and valve 50a into fractionating column 20a at a point intermediate between bubble trays 2|a as a means of increasing the degree of rectication obtained through the combined use of the fractionating columns 3a land 20a. A portion of the liquid which flows downward over bubble plates 5a may be withdrawn from the fractionating. column 3a, through a portion of the pipe 49a, and through a pipe Sla. and a valve 52a and through a cooler 53a and may be delivered by a pump 54a which is mounted in pipe 5Ia into the pipe la and through valve 4a to cool the liquid which is expanded through valve 4a and to wash the parts of the valve a and maintain these parts in a workable condition.

Conversion of hydrocarbons will takeplace in the pipe la and the maintenanceof higher pressures in the pipe la, will result in increased conversion of gas to liquid therein. Although some conversion of gas to liquid may be obtained in the pipe la under pressure below 500 pounds-per square inch, I will preferably maintain pressure in the pipe la above 500 pounds per square inch. Insofar as conversion of gases to liquids is concerned it would be advantageous to maintain a pressure in the pipe la of- 5000pounds, or up- Wards; however, the maintenance of such a pressure in a commercial unit of this type would be impractical as no materials of construction are available from which such a unit could be economically constructed for commercial use.

I have confined` mixtures of fuel oil andcracked gas and heated the conned mixture to temperatures as high as 900 F. noting the pressure set up by the heated mixtures and found that equilibrium pressure for these mixtures at 850 F. and higher' are 3000 pounds per square inch and higher; The apparatus which I usedwas constructed for a maximum operating pres-- sure of 4000 pounds per square' inchat 900 F. and I found that a mixture of light gas and gas oil set up 4000 pounds per square inchl pressure when heated to 900 F. 'Ihese were they maximum conditions under which I made tests. I have tested many diierent mixtures of cracked gas and fuel oil and find that equilibrium pressures for various mixtures taken at the same temperature Vary widely. Good results may be obtained when converting these mixtures under pressures below equilibrium pressure, andfor practical reasons I intend to sooperate. It is desirable to vary the pressure maintained in the pipe I a.. When converting mixtures of gas andfuel oil which have highv equilibrium pressures I- intend to convert under higher pressures and vice versa.

I have converted various mixtures of cracked gas and fuel oil in a tube similar to the pipe I a under pressures ranging from 1000 pounds per square inch to 3000 pounds per square inch and at temperatures ranging from 910 F. and lower and I find that in order to obtain a maximum yield of gasoline from the various mixtures which I have tried it is necessary to alter both the temperature and pressure under Which the conversion of the various mixtures is obtained. Also the composition of the gasoline produced varies with the pressure of conversion.

In order to secure iiexibility of operation I intend to construct the pipe la to hold as much as 3000 pounds pressure per square inch at 900 F. and by manipulation of the valve 4a, try various conversion conditions of both temperature and pressure to ascertain the best conversion conditions for any particular mixture. The results oi the many tests Which I have conducted indicate that for the production of gasoline the best conversion temperature Will be close to 850 F. and the best conversion pressure will be between 1000 pounds per square inch and 3000 pounds per square inch.

By means of operating the valves I9a, 50a, 59a and lla, I Will normally maintain a pressure in the fractionating column 3a, and separator 8a, and the absorber i3d and in interconnecting lines suiiiciently high so that gases leaving the top of fractionating column 3a through pipe 6a, will be stripped of gasoline vapors. This pressure should be maintained at from 250 pounds to 400 pounds per square inch. There is no reason Why this pressure should not be maintained above 400 pounds per square inch except that the cost of equipment would be correspondingly higher. If this pressure is maintained below 250 pounds per square inch and the temperature of cooling Water used in condenser 'la is 90 F. to 100 F. some gasoline will escape through this condenser with the gas which leaves the top of fractionating column 3a. By means of a valve 59a which is disposed in pipe I4a. the pressure in absorber I3a may be held lower th-an the pressure held in separator 8a.

By means of operating valves 29a, 3io, Ma, and 39a, a pressure only sufficient to cause condensation of gasoline vapors in the column 3a will be maintained in the fractionating column 20a and the accumulator 24a and interconnecting lines.

This process may be started in operation by charging fuel oil only through the pipe la and as soon as any gas is produced as a result of so charging fuel oil to the process a portion of this gas Will be liqueed by the incoming charge of oil and will be added thereto. It should be noted particularly that by this process comparatively heavy oils may be converted to gasoline and that gas which results from such conversion may be returned through the process and thereby reconverted and liqueed. Gas obtained from a source extraneous to the process may or may not be processed as dictated by any particular set of circumstances.

While I have illustrated and described certain methods in such manner that the same may be readily understood by those skilled in the art, I am aware that changes may be made in the details disclosed without departing from the spirit of the invention, as expressed in the appended claims.

What is claimed and desired to be secured by Letters Patent is:

1. A process for producing motor fuel with a high anti-knock rating from a mixture of normally gaseous and normally liquid hydrocarbons, said process comprising passing said mixture through a conversion zone at a pressure above 2000 pounds per square inch and at a temperature adapted to effect conversion at said pressure, then passing the converted products directly to a rst separating zone at a pressure substantially lower than that of the conversion zone and appreciably above atmospheric and at a temperature insuflicient to eiect conversion but suflicient A to separate said products into a lighter than gasoline fraction and a second fraction consisting of gasoline and heavier hydrocarbons, said lighter than gasoline fraction comprising a substantial portion of iixed gas and -a substantial portion of normally gaseous hydrocarbons, condensing said normally gaseous hydrocarbons and venting off said fixed gas, returning a portion ofthe condensed normally gaseous hydrocarbons in liquid condition to said first separating zone and another portion to the inlet of said conversion zone, and passing the said second fraction into a second separating zone at a pressure appreciably lower than that of the first separating zone and not appreciably above atmospheric and at a temperature adapted to effect removal of all gasoline fractions from said second fraction in said second separating Zone.

2. A process for manufacturing motor fuel with a high anti-knock rating from a mixture of normally gaseous and normally liquid hydrocarbons, comprising passing said mixture in a restricted stream through a heating zone while heatingl the same to a conversion temperature and maintaining the mixture at a pressure above 2000 pounds per square inch; then passing the resultant converted products directly to a rst separating Zone at a pressure intermediate the heating zone pressure and atmospheric pressure and at a temperature inadequate to effect conversion but sucient to separate said products into a lighter than gasoline fraction and a second fraction consisting of gasoline and heavier hydrocarbons, said lighter than gasoline fraction comprising a substantial portion of xed gas and a substantial portion of normally gaseous hydrocarbons, condensing said normally gaseous hydrocarbons and venting ofi said fixed gas, returning a portion of the condensed normally gaseous hydrocarbons to said first separating zone and another portion to the inlet of said conversion zone, passing the said second fraction into a second separating zone at a pressure appreciably lower than that of the first separating zone and not appreciably above atmospheric and at a temperature adapted to effect removal of all gasoline fractions from said second fraction in said second separating zone and circulating a por-v tion of the heavier than gasoline material from said second separating Zone through a heater and back to said second separating Zone for furnishing the necessary heat in the second fractionating zone to vapo-rize the said gasoline therefrom.

MALCOLM P. YOU'KER. 

